Methylisothiazolinone

AKA “2-Methyl-4-isothiazolin-3-one, 2-Methyl-3(2H)-isothiazolone, 2-Methyl-4-isothiazoline-3-one, N-methylisothiazolone, 3(2H)-Isothiazolone, 2-methyl-3-isothiazolone, n-methylisothiazolin-3-one, Neolone 950”

Synthetic

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Ingredient Facts

Methylisothiazolinone

AKA: 2-Methyl-4-isothiazolin-3-one, 2-Methyl-3(2H)-isothiazolone, 2-Methyl-4-isothiazoline-3-one, N-methylisothiazolone, 3(2H)-Isothiazolone, 2-methyl-3-isothiazolone, N-methylisothiazolin-3-one, Neolone 950

Synthetic · Preservative | Antimicrobial · EWG: 4

Plant-Derived

Preservative

Medicated Active

Synthetic

Clean

A synthetic preservative that keeps products fresh and prevents bacterial growth, used in rinse-off formulas like cleansers and shampoos.

Solubility Solubility in: acetonitrile 78.6; methanol 79.1; hexane 2.371; xylenol 15.65 (g/100 mL)

Formula

C4H5NOS

Mol. Weight

115.16

CAS #

2682-20-4

Form

Liquid

Plant-Derived

Synthetic. Derived from isothiazole, a five-membered heterocyclic compound containing nitrogen and sulfur atoms. Synthesized through chemical reaction of methylamine and isothiazole precursors under controlled conditions.

Function

Preservative | Antimicrobial

Benefits

Preserves Formula

Prevents microbial growth

Traditional Use

Synthesized in the 1970s as a preservative and biocide for cosmetics, personal care, and industrial products. Designed to be a more stable alternative to earlier isothiazolinone preservatives.